APU

Question 1

APU starter cycle limit

Answer 1

3 attemps in 60 minutes

Question 2

Fuel supply for APU

Answer 2

AC or DC pump from Left wing(main) tank

Question 3

Max Altitude for APU Bleed air

Answer 3

17.000 ft

Question 4

APU can be used up to which altitude and carry full generator load

Answer 4

42.000 ft

Question 5

APU privides

Answer 5

Electrical power & bleed air

Question 6

Where do you find APU EGT information

Answer 6

Status page of EICAS, lower EICAS

Question 7

APU control, 2 lights

Answer 7

RUN & FAULT light

Question 8

What happens if you turn off APU battery switch while APU is still running

Answer 8

Automatic shutdown, no fire protection

Question 9

APU shutdown sequence

Answer 9

Moving APU lever to OFF will immediately close apu bleed valve.
APU will start cool down to prevent thermal shock (up to 120s)
After cool down, APU will shut down and RUN light will extinguish

Question 10

APU fire

Answer 10

Automatic shutdown without cool down,
Fire bell sounds
Master warning illuminates
EICAS messages: APU FIRE, APU FAULT

Question 11

APU EICAS message: APU BLEED VAL

Answer 11

The APU BLEED VALVE is not in the commanded position

Question 12

APU EICAS message: APU BTL

Answer 12

The apu fire bottle has been discharged or pressure is low

Question 13

APU EICAS message: APU FAULT

Answer 13

The automatic protection system has been activated or a fire has been sensed

Question 14

APU EICAS message: APU FUEL VAL

Answer 14

Apu fuel valve is not in the commanded position

Question 15

APU EICAS message: APU GEN OFF

Answer 15

The apu gen switch is off with power available or apu generator breaker is open due to a fault

Question 16

APU start sequence

Answer 16

1. Apu bat switch on
2. Stby power rotary switch to AUTO
3. APU selector to start
   (fault light will illuminate briefly - valve transit, RUN light will flash twice)
4. White APU RUN light will illuminate when APU is running at correct speed
5. press APU gen control switch on at elecs panel
6. press APU bleed switch on at pneumatics panel

Question 17

APU powers which elec system

Answer 17

Left AND Right 115 V AC bus

Question 18

APU bleed supplies which pack

Answer 18

Left pack, when crossfeed valve open also right side

Question 19

Which battery do you need to start APU

Answer 19

Both Aircraft and APU batteries

Question 20

What does main battery provide

Answer 20

power to

1. DC fuel pump of left tank
2. APU fuel valve
3. fire protection

Question 21

What does APU battery provide

Answer 21

Power to:

1. APU inlet door
2. APU starter
3. APU control circuits